After watching videos of Hitman, I’ve decided that Hitman is actually an adventure game. Mostly. Two of the hallmarks of adventure games are exploration and puzzle solving.
At the beginning of a level of Hitman, you know very little. The layout of the map and the habits of all the people are largely unknown. Your starting outfit means a lot of places are off-limits, and your starting tools means you aren’t capable too much.
By exploring, you learn more about the level and pick up more tools, giving you more capabilities. One of the most important tools is your disguise. While technically you can probably go anywhere in your trademark suit, getting there unseen is slow and perilous. Disguises and tools then acts as gates to more of the level.
Getting a particular disguise is often a puzzle. Sometimes it’s as simple as distracting someone out of sight of others and subduing them. Other puzzles are more crafted. For example, the person is too well guarded, but if you can find a bartender outfit, now you can poison their drink without looking suspicious, and that will get them to run to the bathroom and away from prying eyes.
So Hitman is a game where you unlock new areas by solving puzzles, which sounds like an adventure game to me. Granted, most of the puzzles are figuring out how to get someone alone, but there are some more intentionally designed ones. The puzzles don’t seem to be as diabolical as traditional adventure games (i.e., try everything in your inventory on every interactive object on the screen) and sometimes are explained by overheard conversations while exploring.